I was keen to create positive buoyancy in the boat, so following some quick calculations;
Personal 162kg x0.5 = 81kg (bike 10kg, clothes 35kg, food 55kg, water 30kg, torches 2kg, tat 30kg)
People 146kg
Anchor + batteries 40kg x0.92 = 100kg (Elecsol 125= 25kg 20m chain + 10m chain= 50kg (chain = 1.35kg/m) 20kg, Anchor (2x) = 24kg
Outboard x 2 17kg + 38 kg x0.88 = 50.44kg
Fibreglass 1000kg x0.33 = 330kg
Steel Keel 500kg x0.92 = 460kg
= Total of 1167kg +25%
= 1458kg boyancy needed = 1458 litres air
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Main Cabin: Headroom . Locker Volume 16cu ft 453 litres (400 rounded down)
Fore Cabin: Locker Volume 16cu ft 453 litres (400 rounded down)
Exterior Cockpit: Volume of lockers under cockpit seats 18cu ft 509 litres (250 rounded down)
+ barrels = 360kg/litre (240 litre)
+ 2X under seat = 200kg/litre (200)
+ under floor 5cm x 150 x 100 = 75 litre (75)
= 1565kg actual
I started out using inflatable exercise balls for floatation
These are gradually being replaced with old 2ltr drinks bottles which are both more robust, and free.
I later added some 120 litre barrels to keep our possessions dry, and help keep her upright in the event of flooding